uni·​cel·​lu·​lar | \ ˌyü-ni-ˈsel-yə-lər \

Definition of unicellular

: having or consisting of a single cell unicellular microorganisms

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Examples of unicellular in a Sentence

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Red tides are caused by a type of unicellular algae known as a dinoflagellate. David Grossman, Popular Mechanics, "What Are Red Tides and Why Are They Getting Worse?," 14 Aug. 2018 But how could habituation happen in unicellular organisms without neurons? Katia Moskvitch, WIRED, "Slime Molds Remember—But Do They Learn?," 14 July 2018 Single cells started to band together, and a world of formless, unicellular life was on course to evolve into the riot of shapes and functions of multicellular life today, from ants to pear trees to people. Katie Langin, Science | AAAS, "Top stories: Chocolate money, the rise of multicellularity, and pet rabbit brains," 29 June 2018 The gulf between unicellular and multicellular life seems almost unbridgeable. Elizabeth Pennisi, Science | AAAS, "The momentous transition to multicellular life may not have been so hard after all," 28 June 2018 Cells in multicellular bodies had to give up much of the freedom of the unicellular lifestyle. Athena Aktipis, Slate Magazine, "Why Cancer Isn’t Going Anywhere," 20 Apr. 2017 The pre-Cambrian is the moment in the history of life when unicellular organisms were ready to take the next step and develop into complex life forms. Ross Andersen, The Atlantic, "How to Jump-Start Life Elsewhere in Our Galaxy," 25 Aug. 2016

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'unicellular.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of unicellular

1858, in the meaning defined above

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unicellular animal



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Time Traveler for unicellular

The first known use of unicellular was in 1858

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More Definitions for unicellular


uni·​cel·​lu·​lar | \ ˌyü-ni-ˈsel-yə-lər \

Medical Definition of unicellular

: having or consisting of a single cell unicellular microorganisms

Other Words from unicellular

unicellularity \ -​ˌsel-​yə-​ˈlar-​ət-​ē \ noun, plural -ties

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